Frequently in the production of several chemical compositions it is important to monitor the progress of a chemical reaction in order to determine when the particular reaction has proceeded to a desired point or to determine whether such reaction is proceeding in the desired manner. Often, such monitoring is accomplished by periodically determining the viscosity of the reaction batch mixture. Thus, there is a need for a viscometer which has the capability of automatically periodically determining the viscosity of a selected reaction mixture.
Moreover, many of the chemical reactions whose progress is desirably so monitored periodically generate large quantities of gas. Such gas generation frequently results in the reaction mixture foaming. It is readily apparent that viscometers which operate on the basis of pressure differentials will not be able to determine the rheological properties of foaming liquids as the presence of gas bubbles in the foam will preclude an accurate reading of the pressure exerted by such liquid. However, what is not readily apparent is that when such a foaming fluid has been passed through a viscometer having pressure taps gas bubbles may become trapped at the junction of such pressure taps and the conduit through which the sample liquid is passed due to the configuration of said junction. The presence of these gas bubbles at such sensitive points will interfere with the accuracy of the pressure readings recorded at later stages of the reaction when the liquid has ceased or decreased its gas production and is thus in a form in which its viscosity may be determined. Hence, there is a need for a viscometer which is capable of accurately automatically periodically determining the rheological properties of a liquid which undergoes periodic rapid gas generation phases.
Although several constructions for viscometers have been proposed in the past, these constructions lack the capability of accurately automatically periodically monitoring the viscosity of sample liquids which periodically undergo gassing or foaming periods, such as are encountered in the production of latexes.
For example, U.S. Pat. No. 3,327,522 discloses a device for turbulent friction measurement. This device comprises a manually operated three-way valve which enables samples to be fed into a piston chamber, a piston which compresses the sample liquid through a vertically disposed narrow tube, and pressure transducers whose taps are disposed perpendicularly along the narrow tube. However, because this viscometer is manually operated, such device is not suitable for automatic periodic operation. Moreover, because of the horizontal configuration of the viscometer's pressure taps the device is not suitable for the automatic periodic determination of viscosities of liquids which undergo periodic foaming.
Therefore, it is an object of this invention to provide a viscometer which is capable of automatically periodically monitoring the viscosity of a chemical reaction.
It is another object of this invention to provide a viscometer which is capable of automatically periodically determining the viscosity of a sample liquid which undergoes periodic phases of gassing or foaming.
The foregoing and additional objects will become more fully apparent from the description and examples hereinafter and the accompanying drawings.